Media Types
Get MIME type from string
The following example shows how to parse a MIME
type from a string using the
mime crate. FromStrError
produces a default MIME
type in an
unwrap_or
clause.
use mime::{Mime, APPLICATION_OCTET_STREAM};
fn main() {
let invalid_mime_type = "i n v a l i d";
let default_mime = invalid_mime_type
.parse::<Mime>()
.unwrap_or(APPLICATION_OCTET_STREAM);
println!(
"MIME for {:?} used default value {:?}",
invalid_mime_type, default_mime
);
let valid_mime_type = "TEXT/PLAIN";
let parsed_mime = valid_mime_type
.parse::<Mime>()
.unwrap_or(APPLICATION_OCTET_STREAM);
println!(
"MIME for {:?} was parsed as {:?}",
valid_mime_type, parsed_mime
);
}
Get MIME type from filename
The following example shows how to return the correct MIME type from a given
filename using the mime crate. The program will check for file extensions
and match against a known list. The return value is mime:Mime
.
use mime::Mime;
fn find_mimetype (filename : &String) -> Mime{
let parts : Vec<&str> = filename.split('.').collect();
let res = match parts.last() {
Some(v) =>
match *v {
"png" => mime::IMAGE_PNG,
"jpg" => mime::IMAGE_JPEG,
"json" => mime::APPLICATION_JSON,
&_ => mime::TEXT_PLAIN,
},
None => mime::TEXT_PLAIN,
};
return res;
}
fn main() {
let filenames = vec!("foobar.jpg", "foo.bar", "foobar.png");
for file in filenames {
let mime = find_mimetype(&file.to_owned());
println!("MIME for {}: {}", file, mime);
}
}
Parse the MIME type of a HTTP response
When receiving a HTTP reponse from reqwest
the MIME type or media type may be
found in the Content-Type header. reqwest::header::HeaderMap::get
retrieves
the header as a reqwest::header::HeaderValue
, which can be converted to a
string. The mime
crate can then parse that, yielding a mime::Mime
value.
The mime
crate also defines some commonly used MIME types.
Note that the reqwest::header
module is exported from the http
crate.
use error_chain::error_chain;
use mime::Mime;
use std::str::FromStr;
use reqwest::header::CONTENT_TYPE;
error_chain! {
foreign_links {
Reqwest(reqwest::Error);
Header(reqwest::header::ToStrError);
Mime(mime::FromStrError);
}
}
#[tokio::main]
async fn main() -> Result<()> {
let response = reqwest::get("https://www.rust-lang.org/logos/rust-logo-32x32.png").await?;
let headers = response.headers();
match headers.get(CONTENT_TYPE) {
None => {
println!("The response does not contain a Content-Type header.");
}
Some(content_type) => {
let content_type = Mime::from_str(content_type.to_str()?)?;
let media_type = match (content_type.type_(), content_type.subtype()) {
(mime::TEXT, mime::HTML) => "a HTML document",
(mime::TEXT, _) => "a text document",
(mime::IMAGE, mime::PNG) => "a PNG image",
(mime::IMAGE, _) => "an image",
_ => "neither text nor image",
};
println!("The reponse contains {}.", media_type);
}
};
Ok(())
}